Extraction blower

ABSTRACT

An extraction blower having a housing having a main air chamber, a debris chamber and a particulate removal port connected to the debris chamber, an impeller configured to rotate within the housing about a central axis and having a base plate positioned in the debris chamber, a plurality of front-facing blades mounted on a front side of the base plate and a plurality of rear-facing blades mounted on a rear side of the base plate.

TECHNICAL FIELD

The present disclosure relates generally to blowers and, more particularly, to extraction blowers for separating solids and/or liquids from an air source.

BACKGROUND

Extraction blowers may be used to blow air obtained from the atmosphere to cool and/or ventilate structures or equipment. The air obtained from the atmosphere may contain solid and/or liquid particles. Thus, extraction blowers are utilized to remove at least some of the solid and/or liquid particles from the obtained atmospheric air to thereby deliver “clean” air for the process of cooling and/or ventilating structures or equipment.

SUMMARY

According to the present disclosure, an extraction blower comprises a housing having a main air chamber, a debris chamber and a particulate removal port connected to the debris chamber, an impeller configured to rotate within the housing about a central axis and having a base plate disposed in the debris chamber and a top plate disposed in the main air chamber, a plurality of front-facing blades mounted on a front side of the base plate between the base plate and the top plate, and a plurality of rear-facing blades mounted on a rear side of the base plate.

These and other aspects, features and advantages of the present disclosure will become apparent in light of the following detailed description of non-limiting embodiments, with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an exemplary extraction blower;

FIG. 2 is a rear view of an exemplary extraction blower;

FIG. 3 is a cutaway view of the interior space of the hood of an exemplary extraction blower;

FIG. 4 is a cutaway, perspective view of a housing with an impeller of an exemplary extraction blower;

FIG. 5 is another cutaway, perspective view of a housing with an impeller of an exemplary extraction blower;

FIG. 6 is a bottom view of an exemplary extraction blower;

FIG. 7 is a side view of an exemplary impeller; and

FIG. 8 is a perspective view of an exemplary impeller.

DETAILED DESCRIPTION

Before the various embodiments are described in further detail, it is to be understood that the invention is not limited to the particular embodiments described. It will be understood by one of ordinary skill in the art that the devices described herein may be adapted and modified as is appropriate for the application being addressed and that the devices described herein may be employed in other suitable applications, and that such other additions and modifications will not depart from the scope thereof.

Although various features have been shown in different figures for simplicity, it should be readily apparent to one of skill in the art that the various features may be combined without departing from the scope of the present disclosure.

With reference to FIGS. 1-3, an extraction blower is shown according to an embodiment of the present disclosure. The extraction blower 10 comprises a motor 100, a housing 200, a hood 300 and an impeller 400 configured to be driven by the motor 100 and configured to rotate within the housing 200. The motor 100 of the extraction blower 10 may be an electric motor comprising a rotating output shaft (not shown).

Referring to FIGS. 4 and 5, the housing 200 defines an air intake opening 202, a shaft opening 204, a partition opening 208, a main air chamber 210, a debris chamber 212, an air outlet 214 and particulate removal ports 218. The housing 200 comprises a front housing wall 220, a rear housing wall 222, a partition wall 224, a side housing wall 228, a bottom support 230 and particulate removal conduits 232.

The front housing wall 220 defines the air intake opening 202. The rear housing wall 222 defines the shaft opening 204. The partition wall 224 defines the partition opening 208. As shown in FIGS. 4 and 5, the air intake opening 202, the shaft opening 204 and the partition opening 208 are circular in shape, although of different sizes. The bottom support 230 defines the air outlet 214, which is shown as a large rectangular opening at the bottom of the housing 200. The side housing wall 228 and rear housing wall 222 define the particulate removal ports 218. As shown in FIGS. 4 and 5, the particulate removal ports 218 are circular openings in the side housing wall 228 and rear housing wall 222. As shown, at least one of the particulate removal ports 218 is formed substantially perpendicular to the central axis 408 and at least another particulate removal port 218 is formed substantially parallel to the central axis 408. The particulate removal conduits 232 extend around and outwardly from the particulate removal ports 218 in the side housing wall 228 and rear housing wall 222. As shown in FIGS. 4 and 5, the particulate removal conduits 232 have a cylindrical shape and extend outwardly from the housing 200 to lead away the particulates removed from the air.

As shown in FIGS. 4 and 5, the front housing wall 220, rear housing wall 222, side housing wall 228 and bottom support 230 are connected together to delimit an interior space of the housing 200. The side housing wall 228 is disposed between the front housing wall 220 and rear housing wall 222 and is connected to the perimeter edges of the front housing wall 220 and rear housing wall 222. The bottom support 230 is also disposed between the front housing wall 220 and rear housing wall 222 and is connected to the bottom edges of the front housing wall 220 and rear housing wall 222. Further, the partition wall 224 is disposed inside the interior space of the housing between the front housing wall 220 and the rear housing wall 222, to delimit the main air chamber 210 and the debris chamber 212 of the housing 200. The perimeter edge of the partition wall 224 is connected to the side housing wall 228. Further, a debris chamber wall 226 is disposed between the partition wall 224 and the rear housing wall 222 around the perimeter edge of the partition wall 224.

Collectively, the front housing wall 220, partition wall 224 and side housing wall 228 define the main air chamber 210. Collectively, the rear housing wall 222, partition wall 224, debris chamber wall 226 and side housing wall 228 define the debris chamber 212. The partition wall 224 and debris chamber wall 226 completely separate the debris chamber 212 from the main air chamber 210, except for the connection of the debris chamber 212 and the main air chamber 210 through the partition opening 208 in the partition wall 224.

The front housing wall 220, rear housing wall 222 and side housing wall 228 are shaped and configured to form the housing 200 in a generally volute shape 234. As shown in FIGS. 2, 4 and 5, the generally volute shape 234 includes a circular portion 238 and a tail portion 240. The air outlet 214 defined by the bottom support 230 is arranged at the bottom of the tail portion 240. Which side of the circular portion 238 the tail portion 240 is formed is a matter of design choice when constructing an extraction blower 10 depending on the intended direction of rotation of the impeller 400.

While not shown in the drawings, the side housing wall 228 may define an access opening that may be covered by an access panel. The access opening permits servicing and cleaning of the housing 200, hood 300 and impeller 400 without requiring significant disassembly of the extraction blower 10.

Referring to FIGS. 1 and 3, the hood 300 defines an air inlet chamber 302, an air inlet 304, an extension opening 308 and an access opening 310. The hood 300 comprises a front hood wall 312, a rear hood wall 314, an extension lip 318, a side hood wall 320, a grate 322 and an access panel 324.

The side hood wall 320 is positioned between the front hood wall 312 and the rear hood wall 314, and is connected to the perimeter edges of the front hood wall 312 and the rear hood wall 314 to define the air inlet chamber 302. Collectively, the bottom edges of the front hood wall 312, rear hood wall 314 and side hood wall 320 define the air inlet 304 for allowing air to enter the air inlet chamber 302. The side hood wall 320 is configured to form a rounded top opposite the air inlet 304. The grate 322 is positioned at the air inlet 304 to prevent large debris from entering the extraction blower 10 during operation. The rear hood wall 314 defines the extension opening 308. The extension lip 318 is disposed around the extension opening 308 and extends from the rear hood wall 314 in a direction away from the front hood wall 312. The front hood wall 312 defines the access opening 310, which is covered by access panel 324.

The hood 300 is configured to be connected to the housing 200 so that the rear hood wall 314 abuts the front housing wall 220. As shown in FIGS. 1 and 3, the extension opening 308 of the hood 300 and the air intake opening 202 of the housing 200 are configured and sized to connect with each other when the hood 300 is connected to the housing 200. In particular, the extension opening 308 of the hood 300 and the air intake opening 202 of the housing 200 are configured, so that the extension lip 318 of the hood 300 extends into the main air chamber 210 of the housing 200 when the hood 300 is connected to the housing 200. The extension lip 318 is rounded and causes the air to more efficiently flow from the air inlet chamber 302 of the hood 300 toward the impeller 400 disposed in the housing 200.

FIG. 3 shows a cutaway view into the interior space of the hood 300. As shown in FIG. 3, connection of the hood 300 to the housing 200 may be accomplished by connections 330 that connect the rear hood wall 314 to the front housing wall 220 from the interior of the hood 300. An advantage of having the connections 330 disposed on the rear hood wall 314 inside the hood 300, rather than on an external flange, is that the dimensions of the rear hood wall 314 can be made large relative to the front housing wall 220, because there is no need to accommodate an external flange for the connections 330. Thus, a desired internal volume of the air inlet chamber 302 may be achieved with a shorter depth, which makes the hood 300 more compact. While the internal connections 330 are shown as bolt attachments, it should be understood that the internal connections 330 may be of other connection types as known by those of ordinary skill in the art, including without limitation screws, rivets, or clasps. Further, while a specific number of internal connections 330 are shown, it should be understood that in accordance with the present disclosure the number of internal connections 330 may vary to be greater or lesser in number.

FIG. 1 shows the access panel 324 detached from the front hood wall 312 so that the access opening 310 is visible. Similar to the access opening and access panel that the side housing wall 228 may accommodate as described above, the access panel 324 allows servicing and cleaning of the impeller 400, main air chamber 210 and debris chamber 212 without having to remove the hood 300. While the access panel 324 is shown in FIG. 1 as being rectangular in shape, it should be understood that the access panel 324 may be any suitable shape, including without limitation a square, an oval, or a circle. The access panel 324 can be attached to the front hood wall 312 through the use of access panel bolts 328. The access panel 324 is sized to entirely cover the access opening 310 when the access panel 324 is attached to the front hood wall 312. Instead of access panel bolts 328, it should be readily understood that the access panel 324 can be mounted to the front hood wall 312 in different manners, including screws, latches, clasps, magnets, hooks, sliding retention members, and/or other fasteners known to those of ordinary skill in the art. Alternatively, the access panel 324 can be mounted with a hinge to make the access panel “door-like” in the respect that it can reveal the access opening 310 by moving the access panel 324 from a closed position where the access opening 310 is completely covered to an open position where the access opening is revealed. The access panel 324 may be configured to completely cover the access opening 310 in such a way so as to prevent air flow through the access opening 310, i.e., configured to be “air-tight.” This may be accomplished through a tight fitting of the access panel 324 to the front hood wall 312 and/or through the use of rubber seals or gaskets disposed between the access panel 324 and the front hood wall 312 or in other ways as known by those of ordinary skill in the art.

Referring to FIGS. 7 and 8, the impeller 400 defines a front end opening 402, a shaft channel 404, a central axis 408 and a plurality of notches 410. The impeller 400 comprises a base plate 412, a collar 414, front-facing blades 418, a top plate 420, rear-facing blades 422 and diverters 424.

The base plate 412 has a flat ring shape that defines a base plate opening 413. The collar 414 has a tubular shape that defines a central bore 415. One side of each of the front-facing blades 418 is connected to the front side of the base plate 412. The front-facing blades 418 are connected to the base plate 412 along different radii and are evenly angularly spaced around the base plate 412. On another side opposite the side connected to the base plate 412, each of the front-facing blades 418 is connected to the back side of the top plate 420. The top plate 420 also has a flat ring shape and defines a top plate opening 421. The front-facing blades 418 are connected to the top plate 420 along different radii and are evenly angularly spaced around the top plate 420. Accordingly, the front-facing blades 418 are disposed between the base plate 412 and the top plate 420 and extend transversely to the planes of both the base plate 412 and the top plate 420.

Each of the front-facing blades 418 is planar and comprises a base edge 430, a top edge 432, an inner edge 434, a curvilinear edge 436, an outer edge 438, a notch 410 and a hole 428. As shown in FIG. 7, the base edge 430 is disposed opposite and parallel to the top edge 432. The inner edge 434 and curvilinear edge 436 are disposed between the base edge 430 and the top edge 432 in the region of the front-facing blade 418 that is disposed radially inward toward the central axis 408 of the impeller 400. The inner edge 434 is straight and extends perpendicularly from the base edge 430 toward the top edge 432. The curvilinear edge 436 extends from the end of the inner edge 434 to the top edge 432. Thus, the inner edge 434 and curvilinear edge 436 together connect the base edge 430 and the top edge 432. The outer edge 438 disposed between the base edge 430 and the top edge 432 in the region of the front-facing blade 418 that is disposed radially outward away from the central axis 408 of the impeller 400. The outer edge 438 defines a notch 410 in the corner of the front-facing blade 418 adjacent the base edge 430. The notches 410 in each of the front-facing blades 418 can be said to give the impeller 400 a “stepped construction,” which allows the full diameter of the impeller blades to be disposed in the main air chamber 210 and a reduced diameter of the impeller blades to be disposed in the debris chamber 212 Although, notches 410 are shown as rectangular in shape, it should be readily understood that the notches 410 may take on any other suitable shape. Adjacent to the outer edge 438 are disposed holes 428 configured to receive weights (e.g., bolts) for balancing rotation of the impeller 400.

The tubular collar 414 is connected to the front side of the base plate 412 extending transversely to the plane of the base plate 412 such that the longitudinal axis of the central bore 415 runs along the central axis 408 of the impeller 400. The radius of the central bore 415 of the collar 414 is sized and configured to match the radius of the circular base plate opening 413 in the base plate 412, so that the base plate opening 413 and the central bore 415 define the shaft channel 404 that accepts the rotating output shaft of the motor 100. The central axis 408 runs through the shaft channel 404 and is substantially perpendicular to the plane of the base plate 412. The impeller 400 is configured to rotate about the central axis 408.

The base edge 430 of each of the front-facing blades 418 is connected to the front face of the base plate 412. Accordingly, as shown, the length of the base edge 430 is preferably the same as the radial dimension of the annulus of the base plate 412. The inner edge 434 of each of the front-facing blades 418 is connected to the side of the collar 414. Accordingly, as shown, the length of the inner edge 434 is preferably the same as the length of the tubular collar 414. The top edge 432 of each of the front-facing blades 418 is connected to the back face of the top plate 420. Accordingly, as shown, the length of the top edge 432 is preferably the same as the radial dimension of the annulus of the top plate 420. As shown in FIGS. 7 and 8, the top plate opening 421 defines the front end opening 402 of the impeller 400. As shown, the radius of the top plate opening 421 is large compared to the radius of the base plate opening 413. The top plate opening 421 is the opening through which air is drawn into the housing 200 by impeller 400, whereas the base plate opening 413 is the opening that accommodates the rotating output shaft of motor 100.

As shown, the rear-facing blades 422 are disposed on the back side of the base plate 412 opposite the front-facing blades 418 and are radially aligned with the front-facing blades 418. Accordingly, as shown in FIGS. 7 and 8, the number of rear-facing blades 422 is the same as the number of front-facing blades 418. The rear-facing blades 422 have a generally triangular shape. Each of the rear-facing blades 422 is disposed on the rear side of the base plate 412 so that the rear-facing blade 422 tapers in a radially inward direction toward the central axis 408 of the impeller 400.

The diverters 424 are disposed on one side of each of the front-facing blades 418, preferably perpendicularly to the plane of the front-facing blades 418. The diverters 424 are disposed on the side of the front-facing blades 418 that leads relative to the rotation of the impeller 400 (i.e., the leading side, not the trailing side). Thus, which side of the front-facing blades 418 the diverters are disposed on depends on the direction of the rotation of the impeller 400. The diverters 424 have a generally planar rectangular shape. As shown, a first end 440 of the diverter 424 is disposed adjacent to the junction of the top edge 432 and curvilinear edge 436 of the front-facing blade 418, and a second end 442 of the diverter 424 is disposed adjacent to the notch 410 of the front-facing blade 418. As shown in FIG. 7 the first end 440 is radially closer to the central axis 408 than the second end 442, such that the diverter is inclined toward the central axis 408.

As shown in FIGS. 4 and 5, the impeller 400 is disposed inside the housing 200 so that the top plate 420 is positioned in the main air chamber 210 and the base plate 412 is positioned in the debris chamber 212. The notches 410 of the front-facing blades 418 accommodate the partition wall 224 so that the partition wall 224 extends radially inward (toward the central axis 408) of the most radially outward portion of the outer edge 438 of each of the front-facing blades 418. Accordingly, as shown, a portion of the front-facing blades 418 are disposed in the main air chamber 210 on one side of the partition wall 224 and another portion of the front-facing blades 418 are disposed in the debris chamber 212 on the other side of the partition wall 224.

As shown in FIGS. 4 and 5, the housing 200 and the impeller 400 are sized and configured so that the front end opening 402 of the impeller 400 is disposed adjacent to the air intake opening 202 of the housing 200 so that air can flow from the air inlet chamber 302 of the hood 300 toward the main air chamber 210 of the housing 200. As shown, the outermost radius of the top plate 420 is about the same as the radius of the air intake opening 202. Also, as shown in FIGS. 4 and 5, the housing 200 and the impeller 400 are sized and configured so that the shaft channel 404 of the impeller 400 is disposed adjacent to the shaft opening 204 of the housing 200. As shown, the radius of the shaft channel 404 is about the same as the radius of the shaft opening 204 to accommodate the rotating output shaft of the motor 100 that extends through the shaft opening 204 of the housing 200 and into the shaft channel 404 of the impeller 400.

In operation, the motor 100 drives an output shaft (not shown) that causes the impeller 400 to rotate within the housing 200. The rotation of the impeller 400 causes air from outside of the extraction blower 10 to flow through the air inlet 304 and then into the air inlet chamber 302. One purpose of the grate 322 being positioned at the air inlet 304 is to prevent relatively large sized particulates from entering the extraction blower 10 during operation. The air then flows through the extension opening 308 and through the air intake opening 202 of the housing 200. The extension lip 318 causes the air to more efficiently flow from the air inlet chamber 302 of the hood 300 toward the impeller 400 disposed in the housing 200. The air then flows through the front end opening 402 of the impeller 400 inside the main air chamber 210. As air enters the housing 200, debris in the air may enter the front end opening 402 of the impeller 400 and move directly into the debris chamber and hit the base plate 412 or, alternatively, debris in the air may hit the front-facing blades 418 in the main air chamber 210. As the debris in the air hits the front-facing blades 418, it is guided by the diverters 424 from the main air chamber 210 toward the debris chamber 212. Once the particulates have reached the debris chamber 212, the angular momentum imparted to the particulates by rotation of the front-facing blades 418, the base plate 412 and/or the air flow in the housing 200 generated by the impeller 400 causes the particulates to move radially outward along or near the base plate 412 and eventually to exit the debris chamber 212 through one of the particulate removal ports 218 and its respective particulate removal conduit 232 to an area outside of the extraction blower 10. Thus, by rotation of the impeller 400, debris is removed from the air in the main air chamber 210 and the clean air flows through the air outlet 214 to an area outside of the extraction blower 10.

The particulate removal port 218 that is formed substantially perpendicular to the central axis 408 is formed in side of housing 200 so as to be substantially in alignment with an air flow generated by the impeller 400 during operation. An advantage of having at least one particulate removal port 218 formed in the side of the housing 200 substantially in alignment with a generated air flow is that moving particulates are not required to change direction in their travel path in order to exit the debris chamber 212. This arrangement allows for a relatively quick and efficient exit of the particulates from the debris chamber 212. It is also advantageous that the particulate removal ports 218 are formed relatively low in the debris chamber 212 in order to naturally serve as a drain for moisture and water even when the extraction blower 10 is not in operation. However, it should be readily understood that the particulate removal ports 218 may be formed additionally and/or alternatively elsewhere in the debris chamber as well.

The rear-facing blades 422 mounted or connected on the rear side of the base plate 412 advantageously impart more air flow into the debris chamber 212, which thereby supports more particulates and/or greater chance for particulates to eventually exit through one of the particulate removal ports 218 instead of the air outlet 214.

While the impeller 400 of an exemplary extraction blower 10 has been shown with the rear-facing blades 422 generally aligning with the front-facing blades 418 on the opposite side of the base plate 412, e.g. as seen in FIG. 8, it should be understood that in accordance with principles of the present disclosure that the rear-facing blades 422 can be staggered so as to not align with the front-facing blades 418 on the opposite side of the base plate 412. Moreover, while the drawings show an embodiment having six front-facing blades 418 and six rear-facing blades 422, it should be understood that there may be a larger or smaller number of front-facing blades 418 and rear-facing blades 422. Furthermore, while the number of rear-facing blades 422 is the same as the number of front-facing blades 418, it should be understood that that the number of rear-facing blades 422 may be different than the number of front-facing blades 418.

With reference to FIGS. 7 and 8, the holes 428 on the impeller 400 provide an optional means for balancing the impeller 400. While the holes 428 are shown near the stepped construction of the front-facing blades 418, it should be understood that the holes 428 can be formed in other areas of the front-facing blades 418 as an alternative or in addition to the shown holes 428.

The present disclosure advantageously describes an extraction blower 10 that can be suitably modified for a wide range of extraction blower 10 sizes and/or motor 100 capacities. Thus, embodiments in accordance with the present disclosure are advantageously scalable in size to achieve a variety of different applications.

While the present disclosure has been illustrated and described with respect to particular embodiments thereof, it should be appreciated by those of ordinary skill in the art that various modifications to this disclosure may be made without departing from the spirit and scope of the present disclosure. 

What is claimed is:
 1. An extraction blower comprising: a housing having a main air chamber, a debris chamber and a particulate removal port connected to the debris chamber; an impeller configured to rotate within the housing about a central axis and having a base plate positioned in the debris chamber; a plurality of front-facing blades mounted on a front side of the base plate; and a plurality of rear-facing blades mounted on a rear side of the base plate.
 2. The extraction blower of claim 1, wherein the particulate removal port is formed substantially toward a bottom end of the debris chamber.
 3. The extraction blower of claim 1, wherein the particulate removal port is formed substantially parallel to the direction of the central axis.
 4. The extraction blower of claim 1, wherein the particulate removal port is formed substantially perpendicular to the direction of the central axis.
 5. The extraction blower of claim 1, wherein the particulate removal port is formed substantially in alignment with an air flow generated by the impeller when in operation.
 6. The extraction blower of claim 1, wherein at least one of the front-facing blades has a hole formed therein.
 7. The extraction blower of claim 1, wherein each of the rear-facing blades extends furthest from the rear side of the base plate at the radially outer most part of the base plate from the central axis.
 8. The extraction blower of claim 1, wherein each of the rear-facing blades is triangle shaped.
 9. The extraction blower of claim 1, wherein the housing further comprises a partition positioned between the main air chamber and the debris chamber, and wherein the front-facing blades extend from the front side of the base plate and into the main air chamber.
 10. The extraction blower of claim 9, wherein the front-facing blades have a stepped construction whereby at least a portion of each of the front-facing blades is recessed radially inward, wherein another portion of each of the front-facing blades that is not recessed is positioned in the main air chamber and at least the portion of each of the front-facing blades that is recessed is positioned in the debris chamber and wherein the other portion of each of the front-facing blades that is not recessed extends a larger radial distance from the central axis than the portion of each of the front facing blades that is recessed.
 11. The extraction blower of claim 1, further comprising a diverter disposed on one of the front-facing blades and extending substantially perpendicularly from a planar surface of the front facing blade.
 12. The extraction blower of claim 11, wherein the diverter is disposed on a leading surface of one of the front-facing blades with respect to a direction of rotation of the impeller.
 13. The extraction blower of claim 1, further comprising a hood attached to the housing, wherein the hood defines an extension opening and an air inlet and wherein the hood comprises an extension lip disposed around the extension opening.
 14. The extraction blower of claim 13, wherein the hood comprises an access opening and an access panel mounted to the hood, and wherein the access panel is sized and shaped to completely cover the access opening.
 15. The extraction blower of claim 13, wherein the hood is connected to the housing with at least one internal connection disposed inside an interior space of the hood.
 16. An extraction blower comprising: a housing having a main air chamber, a debris chamber and at least two particulate removal ports connected to the debris chamber; an impeller configured to rotate within the housing about a central axis and having a base plate positioned in the debris chamber; and a plurality of front-facing blades mounted on a front side of the base plate.
 17. The extraction blower of claim 16, wherein at least one of the at least two particulate removal ports is formed to align with an air flow generated by the impeller when in operation.
 18. The extraction blower of claim 16, wherein a first particulate removal port of the at least two particulate removal ports is formed parallel to the direction of the central axis and a second particulate removal port is formed perpendicular to the direction of the central axis.
 19. The extraction blower of claim 18, wherein the first particulate removal port and the second particulate removal port are formed substantially towards a bottom end of the debris chamber.
 20. An extraction blower comprising: a housing having a main air chamber, a debris chamber and a particulate removal port connected to the debris chamber; a partition connected to the housing and positioned between the main air chamber and the debris chamber; a hood attached to the housing, wherein the hood defines an air inlet, an extension opening and an access opening; an extension lip disposed around the extension opening; an access panel mounted to the hood and completely covering the access opening; an impeller configured to rotate within the housing about a central axis and having a base plate positioned in the debris chamber; a plurality of front-facing blades mounted on a front side of the base plate; a plurality of rear-facing blades mounted on a rear side of the base plate; and a diverter formed on one of the front-facing blades and extending substantially perpendicularly from a planar surface of the front facing blade; wherein at least one of the front-facing blades has a hole formed therein, wherein the front-facing blades extend from the front side of the base plate and into the main air chamber, and wherein the front-facing blades have a stepped construction whereby a first portion of the plurality of front facing blades disposed in the main air chamber extend a larger radial distance from the central axis than a second portion of the plurality of front facing blades disposed in the debris chamber. 